Electrical switching device and contact arrangement therefor

ABSTRACT

Contact arrangement for electrical switching device and electromagnet and armature for alternately moving two switch arms into contact-making and contact-breaking positions. Two spaced contact springs insulated from each other are clamped in a switch housing. A stationary center contact is disposed between the contact springs and has a bifurcated contact end in the form of two legs, one bent tong-like toward one contact spring and the other bent tong-like toward the other contact spring. The two contact springs are biased to engage the stationary contacts and are operated to accommodate one contact spring to engage one stationary contact as the other contact spring is disengaged from the other stationary contact, by a card-like operating member of insulating material carried on the end of the armature. The operating member has a slot intermediate its ends through which one contact spring extends and forms a support at its end opposite the armature for the other contact spring.

United States Patent [191 Aigner ELECTRICAL SWITCHING DEVICE AND CONTACTARRANGEMENT THEREFOR [75] Inventor: Georg Aigner, Munich, Germany [73]Assignee: Siemens AG, Berlin and Munich,

Germany [22] Filed: Apr. 12, 1973 [21] Appl. No.: 350,321

Primary Examiner-Harold Broome Attorney, Agent, or Firm-Hill, Sherman,Meroni, Gross & Simpson [451 Mar. 26, 1974 [5 7] ABSTRACT Contactarrangement for electrical switching device and electromagnet andarmature for alternately moving two switch arms into contact-making andcontactbreaking positions. Two spaced contact springs insulated fromeach other are clamped in a switch housing. A stationary center contactis disposed between the contact springs and has a bifurcatedcontact endin the form of two legs, one bent tong-like toward one contact springand the other bent tong-like toward the other contact spring. The twocontact springs are biased to engage the stationary contacts and areoperated to accommodate one contact spring to engage one stationarycontact as the other contact spring is disengaged from the otherstationary contact, by a card-like operating member of insulatingmaterial carried on the end of the armature. The operating mem ber has aslot intermediate its ends through which one contact spring extends andforms a support at its end opposite the armature for the other contactspring.

5 Claims, 4 Drawing Figures ELECTRICAL SWITCHING DEVICE AND CONTACTARRANGEMENT THEREFOR FIELD OF THE INVENTION Contact arrangement forelectrical switching devices in which two movable contacts on oppositesides of a rigid stationary contact are operated by a common operatingmember.

BACKGROUND, SUMMARY AND ADVANTAGES OF INVENTION Electromagnetic relayshave heretofore attained testing and operating contact forces by meansof the bias of movable contact springs carrying the movable contacts.Such contact arrangements are called selfpressure contact arrangementsand are operated in one'position by the force of an-armature to open onecontact and close the other by the bias of the contact spring. Suchcontact arrangements have a middle contact consisting of a singlecontact leg with a contact rivet on each side of the leg and disposedbetween the movable contacts. In such a contact spring set, the contactdistances are prescribed by the height of the contact rivet as well asby the dimensions of the operating member for disengaging one movablecontact and accommodating the other movable contact to close a circuit.Adjustment of the distances between the movable and stationary contactswith such an arrangement is not feasible in the practical design of arelay and if it were feasible, the best adjustment that can beattainedis an adjustment of one space between the stationary and movablecontacts at the expense of the space between the other stationary andmovable contacts. Moreover, where the middle contact is rigid and singlemovable contactsare on both sides of the movable contact, the distancesbetween the contacts many times are so close that the leakage paths andair paths between the individual contact carriers are too small for manyapplications. The interchanging of large contact rivets on the movablecontacts for smaller contact rivet does not enlarge the leakage pathsand air path to an extent appreciable to make it feasible to attainlarger leakage and air paths by the use oflarger rivets.

By the present invention, the middle contact is divided into two rigidcontact parts tong-like in shape with one contact part spaced upwardlyof the center line extending along the points of connection of thecontact parts and the other contact part extending downwardly of thiscenter line the same distance as the upper contact. With such contactarrangements, however, two rigid center contacts have heretofore beenused requiring the manufacture of two parts, attached separately ininsulating member for the contact springs.

By the arrangement of the present invention, a contact switcharrangement is provided in which a single middle contact is carried inthe insulating block for the movable contacts and has tong-likestationary contact ends extending upwardly and downwardly of the centerline of the middle contact and parallel with each other, with themovable contacts spaced laterally of each other and extending parallelto the part of the middle contact mounted in the insulating base. Thetwo middle contacts are, therefore, generally parallel to the twomovable contact springs on opposite sides thereof.

An advantage of such a design of middle contacts in cooperation withouter, movable contacts is that the distance between the contacts can beadjusted in a simple manner over a far wider range than has heretoforebeen possible where the stationary contacts are on opposite sides of asingle rigid contact member.

A further advantage of the invention is that with the tong-likearrangement of center stationary contacts of the invention, thestationary contacts can be provided with different contacts for specificapplication purposes and the distance of the contact carriers from eachother is increased due to the tong or fork-like arrangement of thestationary contacts, making it possible to use a thicker and more rigidarrangement of stationary contacts than has heretofore been possible.

A further advantage of the present invention is that the transfer ofarmature movement of the relay to the two movable contacts is by acard-like actuating member made from a relatively thick insulatingmaterial and arranged to receive and support the ends of the two movablecontacts to provide a stable actuating connection from the armature ofthe relay to the movable contacts.

The actuating card may be used for a single movable contact as well asfor two contacts and when so used, a slot opening into one side of thecard extends along opposite sides of the single movable contact and isso arranged that the actuating card may be inserted in the switchhousing from its side with the slot spaced in accordance with therequired distance between the stationary and movable contacts whendisengaged.

This actuating card made from insulating material is further ofadvantage where the relays are enclosed in box-like housings totallyenclosing the free ends of the movable contacts and rendering the freeends of these contacts inaccessible.

Other objects, features and advantages of the invention will be readilyapparent from the following description of a preferred embodimentthereof, taken in conjunction with the accompanying drawings, althoughvariations and modifications may be effected without departing from thespirit and scope of the novel concepts of the disclosure.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in side elevation of anelectromagnetic relay constructed in accordance with the principles ofthe present invention with one end wall of the relay removed.

FIG. 2 is a horizontal sectional view taken substantially along line A-Aof FIG. 1.

FIG. 3 is a plan view of an actuating card constructed in accordancewith the principles of the present invention for insertion between thearmature and contact springs from one side of the switch housing; and

FIG. 4 is a top plan view of the card shown in FIG. 3 with the cardinverted for inserting from the opposite side of the switch housing.

DESCRIPTION OF PREFERRED FORM OF THE INVENTION In FIG. 1 of thedrawings, I have shown an electromagnetic relay constructed inaccordance 'with the principles of the invention and carried in ahousing or casing I which may be made of insulating material and magnetcoil 2 having a yoke 3 mounted at one end thereof and extending alongthe top of the magnet coil parallel thereto and forming a pivotalmounting for an armature 4. The armature 4 has one leg 4a extendingalong the core of the coil 2 and a right-angled leg 4b extendingparallel to the coil 2 and having a free end having a slot therein forreceiving a tongue 5b of a rigid actuating card 5. The actuating card 5is shown as being relatively thick in comparison with the contactsoperated thereby and is made from an insulating material to insulatecontacts 6 and 7 from each other as well as move said contacts againsttheir bias. The contacts 6 and 7 are spring-like contacts in the form ofelongated contact springs secured to and extending through inwardlyextending bosslike supports 7a and 7b formed integrally with the housing1 and extending inwardly therealong. A rigid middle contact 8 is carriedbetween the bosses 7a and 7b and may be molded in said bosses andincludes a shank 8a extending for the length of the bosses7a and 7b andhaving a projecting free end which is split tong-like and forms twoparallel vertically spaced contacts 9 and 10 spaced laterally of eachother and extending parallel to the shank 8a. A terminal 8b extends fromthe shank 8a through an end wall of the housing 1 and may serve as asolder contact while a terminal 8c extends'laterally of the contact 8through a side wall of the housing and also may serve as a soldercontact. The solder contacts 8b and 80 may be arranged in accordancewith the direction of installation of the relay and the solderconnection 80 extend from the opposite side wall from that shown wherethe position of the relay during installation is reversed. The contactspring 6 is also provided with two solder connections 6a and 6b. Thecontact spring 7 may be provided with similar solder connections. Thesolder connection 7c is the only solder connection herein shown sincethe other solder connection would be directly beneath the solderconnection 6a.

Referring now in particular to the actuator card 5,

the contact spring 6 abuts the top of said card as shown in FIGQ 3 whilethe contact spring 7 fits within the slot 11 as shown in FIGS. 3 and 4.The lower contact spring 7 is on the upper surface of the slot 111during downward movement of the actuator card and thus breaks thecircuit between the contacts 7 and 10 and accommodates the bias of thespring contact 6 to complete a circuit between the contacts 6 and 9. Inan opposite direction of movement of the armature 4 and leg 4b thereof,the top of the actuator card 5 engaging the bottom of the contact spring6 will open a circuit between the contacts 6 and 9 and the slot 11 willaccommodate the closing of a circuit between the contacts 7 and 10, bythe bias of the contact spring 7.

It will be noted from FIGS. 3 and 4 that the bridge 5a of the actuatorcard is relatively wide in relation to the entire width of the card andthus gives the card sufficient stability to effectively perform itsswitch opening and closing operations and since the slot 11 opens to oneside of the card, the card may be inserted into engagement with thearmature and the contact springs 6 and 7 from one side or the other ofthe switch casing by merely inverting the card. Moreover, the slot 11opening to one side of the actuator card enables a wide bridge to beattained in contrast to a slot in the center of the card, necessitatingsmall bridges on opposite sides of the slot, and making it necessary toinsert the actuator card from the end of the switch casing rather thanfrom either side thereof. Insertion and removal of the bridge from theend of the switch casing cannot be done without removing an end wall ofthe casing to accommodate this operation.

Moreover, with the contact card shown affording an actuating connectionto the two contact springs 6 and 7, the card has sufficient rigidity toeffectively operate over a long period of time and can be fastened tothe armature and contact springs in a straight and vertical assemblywithout requiring the use of screws or other fastening means.

A leaf spring 12 is suitably connected between the yoke 3 and actuatorcard 5 to serve as a return spring for the actuator card and armatureupon deenergization of the coil 2.

I claim as my invention:

1. In an electrical switch and contact arrangement therefor,

a switch casing made from insulating material,

two flat vertically spaced contact springs carried by said switch casingand insulated from each other by said casing,

a stationary contact between said contact springs and insulatedtherefrom, said stationary contact having a shank mounted in theinsulating material of said switch casing and having bifurcatedtong-like contact ends spaced laterally and vertically relative to eachother,

each contact end being aligned with an associated contact spring andbeing generally parallel to each other, and

said contact springs being biased towards said contact ends, and

. actuating means for said contact springs, disengaging one contactspring from its associated contact end and accommodating the othercontact spring to engage its associated contact end by its spring bias.

2. The contact arrangement of claim 1, in which the stationary contacthas a one-part shank having a slot extending along the contact endthereof with a contact end on one side of said slot bent upwardly in anangular direction and then bent parallel to said shank, with the contacton the other side of said slot bent downwardly in an angular directionand then bent to extend parallel to said shank.

3. The electrical switch and contact arrangement of claim 2, wherein theactuatingmeans for the contact springs includes,

an electromagnet,

an armature operated thereby and having a portion extending along theend of said electromagnet'and a right-angled portion extending generallyparallel to said electromagnet, and

an actuator card detachably carried by said electromagnet and havingoperative connection with said contact springs accommodating engagementof one contact spring with its stationary contact by the bias of saidspring and having-actuating engagement with the other of said contactsprings to disengage said contact spring from its associated contactend.

4. The electrical switch and contact arrangement of claim 3,

wherein the actuator card is wider than the combined either side of thecasing depending upon the posi width of the two contact springs, and

wherein a slot opens to one side of said actuator card for receiving oneof said contact springs and so ar- I claim 4, Including a return springreturning said armaranged relative to said actuator card as to provide 5i a mlat-wely wide bridge extending along one Side of ture and actuatorcard upon deenergization of said said slot and connecting opposite endsof said card, electromagnetand accommodating said card to be insertedfrom tion of installation of the switch and casing. 5. The electricalswitch and contact arrangement of

1. In an electrical switch and contact arrangement therefor, a switchcasing made from insulating material, two flat vertically spaced contactsprings carried by said switch casing and insulated from each other bysaid casing, a stationary contact between said contact springs andinsulated therefrom, said stationary contact having a shank mounted inthe insulating material of said switch casing and having bifurcatedtong-like contact ends spaced laterally and vertically relative to eachother, each contact end being aligned with an associated contact springand being generally parallel to each other, and said contact springsbeing biased towards said contact ends, and actuating means for saidcontact springs, disengaging one contact spring from its associatedcontact end and accommodating the other contact spring to engage itsassociated contact end by its spring bias.
 2. The contact arrangement ofclaim 1, in which the stationary contact has a one-part shank having aslot extending along the contact end thereof with a contact end on oneside of said slot bent upwardly in an angular direction and then bentparallel to said shank, with the contact on the other side of said slotbent downwardly in an angular direction and then bent to extend parallelto said shank.
 3. The electrical switch and contact arrangement of claim2, wherein the actuating means for the contact springs includes, anelectromagnet, an armature operated thereby and having a portionextending along the end of said electromagnet and a right-angled portionextending generally parallel to said electromagnet, and an actuator carddetachably carried by said electromagnet and having operative connectionwith said contact springs accommodating engagement of one contact springwith its stationary contact by the bias of said spring and havingactuating engagement with the other of said contact springs to disengagesaid contact spring from its associated contact end.
 4. The electricalswitch and contact arrangement of claim 3, wherein the actuator card iswider than the combined width of the two contact springs, and wherein aslot opens to one side of said actuator card for receiving one of saidcontact springs and so arranged relative to said actuator card as toprovide a relatively wide bridge extending along one side of said slotand connecting opposite ends of said card, and accommodating said cardto be inserted from either side of the casing depending upon theposition of installation of the switch and casing.
 5. The electricalswitch and contact arrangement of claim 4, including a return springreturning said armature and actuator card upon deenergization of saidelectromagnet.